The invention relates to a power supply system.
In Japan, photovoltaic power generators are spreading under the excess power purchasing system.
Moreover, there is a power supply system configured to supply appliances with power from a commercial power supply, photovoltaic power generation and a storage cell while combining power generated by the photovoltaic power generators with the commercial power supply, and also storing the power in the storage cell (for example, Japanese Patent Application Publication No. 2011-15501).
If power supply from a commercial electrical grid falls short of a power demand of the commercial electrical grid due to the unstable power supply from the commercial electrical grid, a power cut may occur in the commercial electrical grid.
In order to reduce an influence of a sudden power cut on consumers, an electric power company divides its power distribution area into local areas, prepares a power supply schedule for each local area in advance, and informs the consumers of the power supply schedule beforehand. Then, the electric power company combines a time slot for supplying power from the commercial electrical grid and a time slot for interrupting the power supply from the commercial electrical grid for each local area, so that the power supply capacity (power generation capacity) can satisfy the power demand in the power distribution area.
However, a power cut in a commercial electrical grid, if it occurs, has various influences on the consumers. For this reason, the electric power company desires to avoid a power cut as much as possible. On the other hand, the consumers desire to secure power by using photovoltaic power generation and a storage cell in the case of a power cut.